US3836630A - Method for treatment of gas containing sulfur dioxide - Google Patents

Method for treatment of gas containing sulfur dioxide Download PDF

Info

Publication number
US3836630A
US3836630A US00237035A US23703572A US3836630A US 3836630 A US3836630 A US 3836630A US 00237035 A US00237035 A US 00237035A US 23703572 A US23703572 A US 23703572A US 3836630 A US3836630 A US 3836630A
Authority
US
United States
Prior art keywords
sulfur dioxide
gas
column
sulfuric acid
oxidizing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00237035A
Other languages
English (en)
Inventor
M Noguchi
H Yanagioka
H Hashimoto
K Abe
T Kanai
K Nishiguchi
Y Kogawa
T Masuko
Z Mashino
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chiyoda Corp
Chiyoda Chemical Engineering and Construction Co Ltd
Original Assignee
Chiyoda Chemical Engineering and Construction Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP5939171A external-priority patent/JPS544903B2/ja
Application filed by Chiyoda Chemical Engineering and Construction Co Ltd filed Critical Chiyoda Chemical Engineering and Construction Co Ltd
Application granted granted Critical
Publication of US3836630A publication Critical patent/US3836630A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/48—Sulfur compounds
    • B01D53/50—Sulfur oxides
    • B01D53/507—Sulfur oxides by treating the gases with other liquids
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/69—Sulfur trioxide; Sulfuric acid
    • C01B17/74—Preparation
    • C01B17/76—Preparation by contact processes
    • C01B17/775—Liquid phase contacting processes or wet catalysis processes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/584—Recycling of catalysts

Definitions

  • the gas can be treated advantageously without requiring the waste water to be discharged out of the system when part of the formed sulfuric acid is used as the absorbent liquid in the absorbing process, the remaining portion of sulfuric acid is used for reaction with a calcium-containing alkali solution to produce harmless gypsum, and the mother liquid is recycled for use as the wash liquid or absorbent liquid for the gas.
  • This invention relates to a method of the treatment of a gas containing sulfur dioxide.
  • One of these methods consists in washing the flue gas with sea water.
  • the sea water which has been used in the treatment is discarded into a river or the sea.
  • the method therefore, only transfers the outlet for the removed sulfur dioxide from the atmosphere to the sea so that the absolute amount of sulfur dioxide discharged remains the same. In this sense, this method gives no fundamental solution to the problem.
  • the flue gas from an ordinary combustion furnace contains solid matters such as soot and ashes and organic substances such as unburnt hydrocarbons and tars in the form of dust. Even if the waste water from the treatment of such smoke is passed through a filter or some other screening means, it still entrains part of the sulfur dioxide and a portion of the ashes in their dissolved state. The waste water in such a state cannot readily be deprived of the dissolved substances. If this waste water is discarded in its unaltered form, therefore, it will give rise to the problem of water pollution.
  • FIG. 1 is a flow sheet illustrating one working example of the method of this invention for the treatment of gas.
  • FIG. 2 is a graph showing the relationship between temperature and percentage of oxidation determined in the oxidation of sulfur dioxide using Mn++ and Fe++ as catalysts.
  • FIG. 3 is a graph showing the relationship between percentage of sulfur dioxide removal and time determined in an experiment wherein Fe+++ was incorporated after the Mn++ catalyst had its activity lowered.
  • FIG. 4 through FIG. 7, incl. are flow sheets illustrating other working examples of the method of this invention.
  • FIG. 8 is a graph showing the change of the percentage of sulfur dioxide removal and that of sulfuric acid concentration with the lapse of operation time determined in an operation carried out by the method of this invention.
  • the first requirement is to create the optimum conditions for the absorp tion of oxygen.
  • the pressure drop in the main current of the gas is desired to be as small as permissible.
  • the catalyst used in this treatment should be capable of retaining its activity for a long time.
  • this invention adopts two separate processes, i.e., a sulfur dioxide absorbing process wherein the sulfur dioxide present in the gas is absorbed by the absorbent liquid to purify the gas and an oxidizing process in which the solution now containing the absorbed sulfur dioxide is subjected to oxidation in the presence of an oxidizing catalyst.
  • the solution which has absorbed sulfur dioxide is induced to absorb air or oxygen under conditions suitable for oxidation.
  • Part of the aqueous solution of sulfuric acid produccd in consequence of the oxidation is circulated to the sulfur dioxide absorbing process.
  • the absorption of sulfur dioxide and the absorption of oxygen are carried out separately under espectively suitable conditions in the present invention.
  • the method of this invention therefore, can treat a large volume of gas containing a relatively small amount of sulfur dioxide, with the pressure drop in the gas flow limited to a very small extent.
  • the oxygen concentration in the ordinary flue gas is smaller than the oxygen concentration in the air.
  • the gas containing sulfur dioxide is introduced via a pipe 5 into the lower section of a sulfur dioxide aborbing column 1, wherein the gas is brought into counterflow contact with dilute sulfuric acid (40% by Weight or below) which has overfiowed a sulfur dioxide oxidizing column 2 and run through a pipe 9.
  • dilute sulfuric acid 50% by Weight or below
  • the sulfur dioxide present in the gas is absorbed by the dilute sulfuric acid and the gas which is now in a purified state is discharged via a pipe 6.
  • the solution which has absorbed sulfur dioxide is forwarded by a pump 3 via a pipe 8 to the sulfur dioxide oxidizing column 2.
  • This discharged gas is returned via a pipe back to the absorbing column 1, wherein the stripped sulfur dioxide is completely absorbed by the dilute sulfuric acid. Thus, there is no possibility that sulfur dioxide will escape out of the system. If the gas discharged from the oxidizing column 2 is perfectly free from sulfur dioxide, then it need not be returned into the atmosphere.
  • the volume of the gas which is forwarded from the oxidizing column 2 to the absorbing column 1 is regulated by means of a valve 4. This valve 4 is used for increasing the pressure inside the oxidizing column 2 so as to increase the velocity of oxygen absorption. Dcpending on the performance of the oxidizing column 2, however, this pressure increase is not always found necessary.
  • the absorbing column 1 Part of the absorbed sulfur dioxide is oxidized in the absorbing column 1, because this column receives supply of the solution which contains the oxidizing catalyst and is forwarded via the pipe 9.
  • the proportion of sulfur dioxide which undergoes oxidization in this column is small compared with the whole sulfur dioxide that is to be oxidized. Even if this oxidation occurs in the absorbing column 1, it does not depart from the object of this invention.
  • the desired types of the absorbing column 1 include those of packed column, spray column and plate column.
  • the oxidizing column 2 is of a bubbling type. For the delivery of air thereto, there may be disposed only one air inlet or two or more air inlets.
  • the sulfuric acid formed in the oxidizing column 2 is withdrawn via a pipe 11 and may be processed as a final product.
  • This function of catalyst activation is particularly conspicuous in the operation using Fe+++ as the catalyst. If a divalent iron ion (which lacks catalytic activity) such as of FeSO is added at first, the iron ion is gradually converted into the trivalent iron ion within the oxidizing column and, in the converted form, functions as any ordinary Fe+++ catalyst.
  • the inventors pursued research on Fe+++ catalysts. Consequently, they have discovered that at temperatures over a certain level, the Fe+++ catalyst manifests activity as great as that of the Mn++ catalyst and that the Fe+++ is not poisoned while Mn++ is susceptible to catalyst poisoning.
  • FIG. 2 is a graph showing the relationship between temperature and percentage of oxidation determined in the oxidation of sulfur dioxide using Mn++ and Fe+++ as catalysts.
  • an acid solution having sulfur dioxide dissolved in 5(Weight) sulfuric acid solution was fed and air was blown each at a constant flow rate into the oxidizing column, with the solution temperature and the catalyst concentration varied in the indicated ranges, to determine the oxidation percentage of sulfur dioxide.
  • Curve A represents the results obtained in the case of -Mn++ catalyst and Curve B those obtained in the case of Fe catalyst respectively.
  • FIG. 3 is a graph indicating that the Fe catalyst exhibited strong resistance to poisoning.
  • the solution was obtained by water-scrubbing a flue gas of asphalt combustion which is considered to poison catalysts most seriously.
  • the resultant solution was concentrated and added at the age of 5 hours of operation into a device point C in FIG. 3 wherein the absorption and oxidation of sulfur dioxide from the water-scrubbing flue gas of asphalt combustion were effected at about 50 C. by using 460 p.p.m. of Mn++ catalyst.
  • the percentage of sulfur dioxide removal fell immediately from about 85% to about 25%.
  • the ratio of removal was brought back to the former level when 5000 p.p.m. of the Fe+++ catalyst was subsequently added.
  • FIG. 3 clearly suggests that the Fe+++ catalyst, unlike the Mn++ catalyst, remains unpoisoned by the impurities present in the flue gas, such as V N0 and organic and inorganic oxidizable substances and that it has activity equal to that of the Mn++ catalyst at the elevated temperatures indicated above.
  • the respective concentrations of the components may be determined in accordance with the gas temperature and the amount and kind of impurities involved.
  • the percentage of oxidation can be retained at substantially the same level in the gas temperature range of from 30 to 80 C. by using 1200 p.p.m. or more of Fe+++ and 60 p.p.m. or more of Mn++.
  • the amount of air When air is used in the oxidizing column 2, it is desirable for the amount of air to be two to five times as great as the theoretical requirement.
  • the amount of air may be slightly in excess of the equivalent Weight where the oxidizing column in use excels in absorption efficiency.
  • Another advantage of this invention resides in the fact that the absorbing column need not be operated strictly for the sole purpose of the absorption of sulfur dioxide.
  • part of sulfur dioxide may be oxidized in the absorbing column.
  • the aqueous solution of sulfuric acid which has been circulated from the oxidizing column contains the oxidizing catalyst. If any oxygen has already been absorbed in the absorbing column, then the oxidation of sulfur dioxide occurs in proportion to the amount of absorbed oxygen. In this sense, the gas which contains oxygen in addition to sulfur dioxide proves to be particularly advantageous. If excess air is fed to the oxidizing column, the excess oxygen is forwarded from the oxidizing column to the absorbing column, in which it is consumed in the oxidation of sulfur dioxide. Consequently, the excess oxygen serves to lessen the load of the oxidizing column in proportion to its amount.
  • the flue gas from a boiler generally has a temperature in the range of from 130 to 170 C.
  • this flue gas is treated by the method of this invention, the gas is first introduced into the absorbing column, wherein it comes into contact with the absorbent liquid and consequently has its temperature sharply lowered. In the meantime, the
  • the gas which is discharged from the absorbing column generally has a temperature in the range of from 50 to C., although it is variable with the gas temperature at the inlet of the column, the composition of the gas, the particular mois ture content in the gas, and the mass and heat transfer performance of the absorbing column. Accordingly, the solution which has absorbed sulfur dioxide and which is now forwarded to the oxidizing column is brought to a temperature suitable for the use of Fe+++ as the catalyst. Therefore, the flue gas from the boiler or some other combustion furnace can be treated without requiring the gas to be cooled or heated by any external source.
  • FIG. 4 is a flow sheet illustrating a device combining in a unified form the absorbing column and the oxidizing column of the preferred embodiment shown in FIG. 1.
  • the gas containing sulfur dioxide is fed through a pipe 5 into the middle section of the absorbing-oxidizing column 14.
  • the gas is brought into contact with dilute sulfuric acid which has flowed down from the upper portion of the column 1 so as to have the sulfur dioxide present in the gas absorbed by the acid.
  • the purified gas obtained after this treatment is discharged out of the system via a pipe 6.
  • the dilute sulfuric acid which has absorbed sulfur dioxide flows down into a oxidizing compartment 16, wherein it comes into contact with oxygen or air being delivered therein via a pipe 7, with the result that the absorbed sulfur dioxide is oxidized in the presence of a catalyst introduced therein via the pipe 13.
  • the formed sulfuric acid is withdrawn as a product via a pipe 11, while part of it is forwarded via a pipe 9 to the absorbing compartment 15 and used therein as the absorbent liquid for sulfur dioxide.
  • the sulfur dioxide stripped in the oxidizing compartment 16 by virtue of the air is again absorbed by the dilute sulfuric acid in the absorbing compartment 15.
  • the oxidizing catalyst which is fed via a pipe 13 functions in much the same way as in the working example of FIG. 1.
  • the catalyst upon degradation of activity, is activated with oxygen inside the oxidizing compartment by entirely the same principle.
  • the flow sheet of FIG. 5 illustrates an embodiment having the oxidizing compartment of the device of FIG. 4 partially modified.
  • the absorbing-oxidizing column 14 is divided into a sulfur dioxide absorbing compartment 15 and a sulfur dioxide oxidizing compartment 16 by disposing a seal pan 17 which is provided at the base with a pipe.
  • the dilute sulfuric acid which has absorbed sulfur dioxide within the absorbing compartment 15 runs down a passage 18 into the lower portion of the oxidizing compartment 16, wherein it comes into contact with oxygen or air being delivered therein via a pipe 7 so that the sulfur dioxide is oxidized therewith. Any excess gas in the oxidizing compartment 16 is permitted to enter the absorbing compartment through gas risers 19 formed across the seal pan 17.
  • the seal pan provides separate passages for the gas and the liquid to establish concurrent flow between the two states of fluid in the oxidizer.
  • the present embodiment has entirely the same function as that of the device of FIG. 1 which has the absorbing column and the oxidizing column as separately constructed units.
  • FIG. 6 is a flow sheet depicting a method for producing gypsum by using the sulfuric acid to be formed in the oxidizing column 2, to cite an example of the utilization of by-produced sulfuric acid.
  • the gas fed via a pipe into the absorbing column 1 comes into counter-current contact with the dilute sulfuric acid which runs down from the upper section of the column 1, so that the sulfur dioxide contained therein is absorbed by the acid.
  • the gas thus purified by the removal of sulfur dioxide is discharged out of the system via a pipe 6.
  • the liquid which has absorbed the sulfur dioxide is forwarded by a pump to the oxidizing column 2, wherein it comes into contact with oxygen or air being delivered therein through a pipe 7 so that the sulfur dioxide contained therein is oxidized.
  • Part of the sulfuric acid formed in the oxidizing column 2 is returned to the absorbing column 1, while the remaining portion of sulfuric acid is delivered through a pipe 11 to a crystallizing tank 20 which is provided with an agitating means.
  • the aqueous solution of sulfuric acid which has been introduced into the crystallizing tank reacts with a calciumcontaining alkali liquid being delivered therein via a pipe 21.
  • the reaction produces gypsum.
  • the agitating means there may be employed a mechanical stirrer. Otherwise, the required turbulent flow of the mixture may be produced by causing air or oxygen meant for delivery to the sulfur dioxide oxidizing column 2 or air for some other purpose to be blown into the crystallizing tank 11 via its bottom.
  • the slurry which contains the crystals of gypsum formed in the crystallizing tank is withdrawn by a pump 22 and then forwarded to a solid-liquid separator 23, wherein it is separated into crystals and mother liquor.
  • the crystals may, as required, be washed with water to afford gypsum of good quality in the form of calcium sulfate bihydrate and then discharged through an outlet 27 of the separator 23.
  • the waste water which results from the washing of crystals and the mother liquid which contains the oxidizing catalyst and which results from the removal of crystals are both sent to a mother liquid tank 24 and then circulated via a pipe 26 to the absorbing column 1 by means of a pump 25.
  • the mother liquor resulting from the removal of crystals is not always required to be returned to the absorbing column. It may be returned to the oxidizing column 2 or to some other suitable process.
  • the present embodiment amounts to addition of a gypsum production process to the device illustrated in FIG. 1. It goes without saying that the gypsum production process described above may be incorporated into the device illustrated in FIG. 4 or that illustrated in FIG. 5.
  • FIG. 7 is a flow sheet illustrating a device formed by incorporating into the device of FIG. '6 a pretreatment process designed for the removal, by washing, of soot and dust so as to permit a unified operation of flue gas treatment.
  • the flue gas from the boiler usually has a temperature in the range of from 130 C. to 170 C. It is introduced via a pipe 29 to the soot scrubber 28, wherein it is washed with the mother liquid injected downwardly from the top of the scrubber. The soot and dust contained in the gas are consequently removed by the liquid. At this time, water is vaporized until the waste gas being introduced is saturated substantially completely with water.
  • the gas discharged through the scrubber 28 is colled to 40- 70 C.
  • a pipe 30 provided for the scrubber 28 is intended to supply water to make up for the water which has been vaporized upon contact with the gas. At the bottom of this scrubber 28 there is collected the aqueous solution which now contains such solid matters as soot and ashes, partially dissolved sulfur dioxide, heavy metals,
  • This aqueous solution is forwarded by a pump 21 to a filter 32 so as to be deprived of solid matters. Thereafter, the aqueous solution is sent to the sulfur dioxide absorbing column 1. This aqueous solution may be sent directly to the sulfur dioxide oxidizing column 2 without being passed through the absorbing column 1.
  • the solid matters which have been separated by the filter 32 are withdrawn out of the system and disposed of by a suitable means. The removed solid matters may be admixed into the by-produced gypsum when the solid matters occur only in a small amount or when the usage of the by-produced gypsum is not affected by the presence of such extraneous matters.
  • the Wash liquid of the scrubber 28 may be delivered by a pump 31 to the absorbing column 1, the oxidizing column 2 or a crystallizing tank 20 so as to have the solid matters admixed eventually into the gypsum.
  • the gas which has been freed of solid matters is fed via a pipe 5 to the bottom of the sulfur dioxide absorbing column 1, wherein it is brought into countercurrent contact with the aqueous solution of sulfuric acid in the same manner as in the absorbing column of FIG. 6, so that the sulfur dioxide present in the gas is absorbed.
  • Sulfurous acid which has absorbed sulfur dioxide in the absorbing column 1 is oxidized in the oxidizing column 2 to form the aqueous solution of sulfuric acid.
  • this aqueous solution of sulfuric acid is returned to the ab sorbing column 1 and is used therein as the absorbent liquid.
  • the remaining portion of the aqueous solution is sent to the crystallizing tank 20, wherein it is allowed to react with a calcium-containing alkali solution to form a slurry containing crystals of gypsum.
  • the slurry is separated by a solid-liquid separator into the crystals of gypsum and the mother liquid.
  • the mother liquid is returned by a pump 25 to the soot-dust scrubber 28 and is used therein as the wash liquid.
  • the gas treating method of the present invention can provide desired removal of sulfur dioxide from the gas without permitting any of the waste water from the treatment to be discharged out of the system. At the same time, it affords preparation of an entirely harmless gypsum as a by-product.
  • a perfect solution to the problem of environmental pollution caused by the gas resides is thus provided by decreasing the absolute amount of sulfur dioxide discharged.
  • the method of the present invention can remove sulfur dioxide by nearly and permit perfect removal of soot and dust which are entrained by the flue gas. From the standpoint of prevention of public nuisance, this is an outstanding method.
  • Example 1 A gas composed of 0.3% by volume of S0 2% by volume of O and the balance of N and having a temperature of 56 C. was delivered at a flow rate of 40 Nm. /hr. to a packed column (200 mm. in diameter and 3,000 mm. in height) filled with Raschig rings 5 mm. in diameter. Through the top of the packed column, 5(weight) dilute sulfuric acid containing 200 ppm. of Mn++ was fed via an oxidizing column at a rate of 1,000 lit/hr. The said gas was brought into contact with the dilute sulfuric acid within the packed column, with a result that the sulfur dioxide present in the gas was absorbed by the dilute sulfuric acid and the purified gas was discharged via the top of the packed column.
  • the liquid which had absorbed sulfur dioxide was continuously extracted through the bottom of the packed column and forwarded at a rate of 1,000 1it./hr. to an oxidizing column which measured 200 mm. in diameter and 6,000 mm. in height and which was pro vided at the lower portion with a dispersing board for air introduction.
  • the dispersing board enabled the aid to ascend in the form of fine bubbles in the oxidizing column.
  • the solution of Mn++ was fed intermittently into the oxidizing column so that the catalyst concentration would be kept above 100 p.p.m. as Mn++.
  • the gas discharged via the top of the oXidiZing column was returned to the bottom of the packed column so as to cause absorption of the sulfur dioxide present in the discharged gas.
  • the gas discharged through the top of the packed column had a sulfur dioxide concentration of from 0.006 to 0.004% by volume.
  • Example 2 A gas having a higher oxygen content than the gas of Example 1 was treated by using the same absorbing column and oxidizing column as those of Example 1.
  • a gas 60 C. of temperature composed of 0.240% by volume of S 20.3% by volume of O and the balance of N was delivered at a flow rate of 30.2 Nm. /hr. into the packed column via the bottom.
  • the gas discharged through the top of the packed column was found to have sulfur dioxide concentration of 60 to 200 p.p.m. by volume.
  • the concentration of sulfuric acid in the circulated liquid was maintained at a level of about 5.6% by weight.
  • the concentration of the catalyst was maintained in the range of 200 to 400 p.p.m. as Mn++ by intermittently feeding MnSO sulfuric acid solution.
  • Example 3 Flue gas discharged from a boiler was treated by using the same device as used in Example 1.
  • the sulfuric acid concentration was maintained at a level of about 5.9% by weight by drawing off the formed sulfuric acid at a rate of 4.6 lit./hr. To make up for the water lost by the vaporization inside the packed column, water was fed at a flow rate of 2.6 lit./hr. with the liquid level kept constant inside the packed column.
  • Example 4 The gas discharged from a sulfur recovery plant was sent through a device like the one shown in FIG. 4, using Fe+++ as the catalyst, to effect removal of sulfur dioxide from the gas.
  • the absorbing-oxidizing column measured 800 mm. in diameter and 13,000 mm. in overall length.
  • the absorbing compartment formed in the upper portion of this column was filled with Raschig rings up to a height of 5,000 mm.
  • the oxidizing compartment formed in the lower portion of the device was practically empty, except 10 sieve plates were disposed equidistantly so as to prevent back mixing of liquid.
  • the gas was composed of 1.2% of S0 3.8% of CO 1.6% of O and 3.9% of H 0 (by volume) and the balance of N It was introduced at a flow rate of 1,000 Nmfi/hr. at C. under normal pressure.
  • the liquid was withdrawn at a rate of 30 Nm. /hr. via the bottom of the device by means of a pump.
  • the withdrawn liquid was introduced into the absorbing compartment via the top and used therein as the absorbent liquid.
  • the air was blown in at a flow rate of 80 Nm. /hr. through the gas dispersing board disposed at the lower portion of the device, so as to permit the sulfur dioxide solution descending from the absorbing compartment to be oxidized by 0 present in the air.
  • the sulfur dioxide concentration in the gas discharged through the top of the device was maintained in the range of from 50 to 100 p.p.m.
  • the formed sulfuric acid was withdrawn at a rate of 0.86 Nm. /hr. and water was fed continuously into the device so that the liquid level therein could be maintained constant.
  • the sulfuric acid concentration of the liquid was about 5.8 to 6.2% by weight.
  • the Fe+++ in the catalyst was adjusted by dissolving Fe (SO in water. It was intermittently fed so that the catalyst concentration within the device could be maintained in the range of from 300 to 500 p.p.m. as Fe+++.
  • the temperature of the gas was lowered to about 49 C. as a result of the vaporization of steam into the gas.
  • the temperature of the circulated liquid was 46 C
  • Example 5 The smoke discharged from a boiler using asphalt as the fuel and composed of 0.3% of S0 9.9% of H 0, 12.2% of CO 2.7% of 0 74.9% of N (by volume) and a trace of impurities was fed at a rate of 13 to 17 NmF/hr. to a scrubber, wherein the impurities were washed down to the bottom of the scrubber.
  • the liquid from the top of the oxidizing column was used as the absorbent liquid. At a sign of rise in the sulfuric acid concentration, the liquid was withdrawn intermittently so as to permit the sulfuric acid concentration in the liquid being treated to remain in the range of 6 to 8% by weight.
  • FIG. 8 graphically indicates the transition of operation of this working example as recorded along the course of time.
  • the upper graph shows the time-course change of the percentage of sulfur dioxide oxidation and the lower graph that of sulfuric acid concentration in the oxidizing column.
  • the adjustment of sulfuric acid concentration as indicated in the upper graph means an operation which consisted of withdrawing the aqueous solution of sulfuric acid from the oxidizing column and adding plain water to the oxidizing column by way of replacement each time the sulfuric acid concentration in the oxidizing column rose to approach 8%.
  • the lower graph clearly indicates that the sulfuric acid concentration was lowered each time adjustment was made in the sulfuric acid concentration.
  • Example 6 Smoke at 159 C. discharged from a boiler using asphalt as the fuel and composed of 0.3% of S 9.9% of H 0, 12.2% of C0 2.7% of 0 74.9% of N (by volume) and 1.8 g./Nm. of soot and dust was treated in a device like the one shown in FIG. 7.
  • the smoke was initially fed at a flow rate of 1,000 Nm. /hr. to a soot scrubber. In the scrubber, it was scrubbed with the aqueous solution being injected at a rate of 300 lit/hr. from the mother liquid tank, so that the gas was freed of solid matters entrained thereby.
  • the discharged gas cooled to about 64 C., was sent to the packed type sulfur dioxide absorbing column 700 mm. in diameter,
  • the absorbent liquid and the liquid which had been used in the scrubber were forwarded at respective rates of about 50,000 lit/hr. and about 230 lit/hr. to the oxidizing column, wherein they were brought into intimate contact with air being fed in at a flow rate of 50 Nmfi/hn, causing the oxidation of sulfur dioxide.
  • the liquid in this case contained about 2,500 p.p.m. of Fe' and p.p.m. of Mn++ as the catalyst.
  • the formed aqueous solution of sulfuric acid was forwarded at a rate of 230 lit/hr. from the oxidizing column to the crystallizing tank and brought into contact with limestone fed at a rate of 12.7 kg./hr. to produce gypsum.
  • the resultant slurry was sent to the centrifugal separator and divided thereby into gypsum crystals and mother liquid.
  • the mother liquid was returned to the soot scrubber. This separation produced gypsum crystals at a rate of about 20.4 kg./hr. It was found to be suitable for the production of gypsum board.
  • Example 7 Smoke at 159 C. discharged from a boiler using heavy oil as the fuel and composed of 0.1% of 50;, 10.1% of H 0, 12.2% of CO 2.7% of 0 74.9% of N (by volume) and 0.2 g./Nm. of soot and dust was initially fed at a flow rate of 1,000 Nm. /hr. to 'a soot scrubber as shown in FIG. 7.
  • the smoke was scrubbed with the aqueous solution being injected at a rate of 100 lit./hr. from the mother liquid tank, so that the gas was freed of solid matters entrained thereby.
  • the discharged gas cooled to about 64 C. was sent to the packed type sulfur dioxide absorbing column 700 mm.
  • the absorbent liquid and the liquid which had been used in the scrubber were forwarded at respective rates of about 50,000 lit./hr. and about 80 lit/hr. to the oxidizing column, wherein they were brought into intimate contact with air being fed in at a flow rate of 30 Nm. /hr., causing the oxidation of sulfur dioxide.
  • the liquid in this case contained about 3,000 p.p.m. of Fe as the catalyst.
  • the formed aqueous solution of sulfuric acid was forwarded at a rate of 80 lit/hr. from the oxidizing column to the crystallizing tank and was brought into contact with limestone fed at a rate of 4.2 kg/hr. to produce gypsum.
  • the resultant slurry was sent to the centrifugal separator and divided thereby into gypsum crystals and mother liquid.
  • the mother liquid was returned to the soot scrubber. This separation produced gypsum crystals at a rate of about 7.4 kg./hr. It was found to be suitable for producing portland cement retarder.
  • Example 8 Flue gas at 220 C. composed of 1.2% of S0 9.9% of H 0, 12.2% of C0 2.7% of 0 74.0% of N (by volume) and 0.2 g./Nm. of soot and dust was initially fed at a flow rate of 1,000 Nm. /hr. to a soot scrubber as shown in FIG. 7.
  • the smoke was scrubbed with the aqueous solution being injected at a rate of 1200 lit./hr..from the mother liquid tank, so that the gas, was freed of solid matters entrained thereby.
  • the discharged gas cooled to about 65 C., was sent to the packed type sulfur dioxide absorbing column 700 mm.
  • the absorbent liquid and the liquid which had been used in the scrubber were forwarded at respective rates of about 50,000 lit/hr. and about 920 lit./hr. to the oxidizing column, wherein they were brought into intimate contact with air being fed in at a flow rate of 150 Nm. /hr., causing the oxidation of sulfur dioxide.
  • the liquid in this case contained about 3,000 p.p.m. of Fe+++ as the catalyst.
  • the formed aqueous solution of sulfuric acid was forwarded at a rate of 920 lit/hr. from the oxidizing column to the crystallizing tank and brought into contact with limestone fed at a rate of 50.8 kg./hr. to produce gypsum.
  • the resultant slurry was sent to the centrifugal separator and divided thereby into gypsum crystals and mother liquid.
  • the mother liquid was returned to the soot-dust scrubber. This separation produced gypsum crystals at a rate of about 81.5 kg./hr.
  • the gypsum obtained comprised 5.3% free Water and a suspension thereof in Water had a pH of 6.5.
  • the gypsum was found to comprise 97.5% CaSO 2H O at dry base, with the balance being as shown below in Table 1.
  • a method for the treatment of waste gas containing sulfur dioxide which method comprises:

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Biomedical Technology (AREA)
  • Health & Medical Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Treating Waste Gases (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
US00237035A 1971-03-29 1972-03-22 Method for treatment of gas containing sulfur dioxide Expired - Lifetime US3836630A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP1819271 1971-03-29
JP4700071 1971-06-28
JP5939171A JPS544903B2 (no) 1971-08-06 1971-08-06

Publications (1)

Publication Number Publication Date
US3836630A true US3836630A (en) 1974-09-17

Family

ID=27282121

Family Applications (1)

Application Number Title Priority Date Filing Date
US00237035A Expired - Lifetime US3836630A (en) 1971-03-29 1972-03-22 Method for treatment of gas containing sulfur dioxide

Country Status (9)

Country Link
US (1) US3836630A (no)
AU (1) AU455259B2 (no)
CA (1) CA970932A (no)
DE (1) DE2215177C3 (no)
FR (1) FR2132186B1 (no)
GB (1) GB1389730A (no)
IT (1) IT969503B (no)
NL (2) NL168321B (no)
SE (1) SE384015B (no)

Cited By (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3920421A (en) * 1974-01-15 1975-11-18 Chemsoil Corp Removal of oxides of nitrogen from gas streams which also contain sulfur dioxide
US3932585A (en) * 1972-09-12 1976-01-13 Nippon Kokan Kabushiki Kaisha Method of removing nitrogen oxides from plant exhaust
US3947546A (en) * 1972-05-31 1976-03-30 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process for the purification of gaseous effluents
US3947560A (en) * 1973-03-15 1976-03-30 Nippon Oil Company, Ltd. Process for oxidizing sulfur dioxide
US3962864A (en) * 1973-09-20 1976-06-15 Rolls-Royce (1971) Limited Gas turbine power plant with exhaust treatments for SO2 removal
US3983217A (en) * 1973-09-26 1976-09-28 Kurashiki Boseki Kabushiki Kaisha Method for removing sulfur dioxide from waste gases
US3988129A (en) * 1974-12-16 1976-10-26 Union Carbide Corporation Process for removing sulfur dioxide from gas streams
US4011298A (en) * 1973-12-18 1977-03-08 Chiyoda Chemical Engineering & Construction Co. Ltd. Method for simultaneous removal of SOx and NOx
US4035470A (en) * 1974-11-02 1977-07-12 Fuji Kasui Engineering Co., Ltd. Process for removing sulfur oxides and/or nitrogen oxides from waste gas
US4061743A (en) * 1975-05-06 1977-12-06 Fuji Kasui Engineering Co., Ltd. Exhaust gas scrubbing process
US4070441A (en) * 1975-01-31 1978-01-24 American Electronic Laboratories, Inc. Method of removing sulfur dioxide from flue gases
US4092401A (en) * 1976-01-09 1978-05-30 Compagnie Royale Asturienne Des Mines Process for reutilization of iron chlorides in aqueous solution
US4100259A (en) * 1973-07-26 1978-07-11 Compagnie Industrielle Des Telecommunications Cit-Alcatel Process and apparatus for the purification of fumes and gases and for the production of sulfuric acid
US4101635A (en) * 1973-09-03 1978-07-18 Nippon Oil Company Ltd. Method for regenerating and recycling catalyst for oxidation of sulfur dioxide
US4123355A (en) * 1977-11-21 1978-10-31 Nasa Simultaneous treatment of SO2 containing stack gases and waste water
US4156712A (en) * 1976-02-28 1979-05-29 Chiyada Chemical Engineering & Construction Co., Ltd. Gas-liquid contacting method
US4239515A (en) * 1976-08-10 1980-12-16 Chiyoda Chemical Engineering & Construction Co., Ltd. Gas-liquid contact reaction apparatus
US4239737A (en) * 1977-01-14 1980-12-16 Italsider S.P.A. Method for removing sulfur dioxide
US4284608A (en) * 1977-07-18 1981-08-18 American Electronic Laboratories, Inc. Process for regenerating sulfur dioxide gas scrubbing solutions
US4420465A (en) * 1981-06-22 1983-12-13 Mitsubishi Jukogyo Kabushiki Kaisha Process for desulfurizing an exhaust gas
US4502901A (en) * 1983-10-19 1985-03-05 National Gypsum Company Manufacture of gypsum board from FGD gypsum
US4552744A (en) * 1984-02-10 1985-11-12 Atomic Energy Of Canada Limited Process for the production of sulfuric acid using coated catalysts
US4657746A (en) * 1985-02-18 1987-04-14 Inco Limited Scrubbing of sulfur dioxide with lime slags
WO1987007527A1 (en) * 1986-06-09 1987-12-17 Northern States Power Company Flue gas scrubber system
WO1988009695A1 (en) * 1987-06-12 1988-12-15 Northern States Power Company Flue gas scrubber system
US4830718A (en) * 1985-10-21 1989-05-16 John Stauffer Removal of sulfur dioxide (SO2) from waste gases and recovery as sulfuric acid
US4861558A (en) * 1986-06-09 1989-08-29 Northern States Power Company Flue gas scrubber system with chloride removal
WO1990012753A1 (en) * 1988-12-30 1990-11-01 Stauffer John E Removal of sulfur dioxide (so2) from waste gases and recovery as sulfuric acid
US4986966A (en) * 1986-06-09 1991-01-22 Northern States Power Company Retrofit flue gas scrubber system
US6531104B1 (en) 2000-11-21 2003-03-11 Alstom (Schweiz) Ag Process for the absorption of sulfur oxides and the production of ammonium sulfate
US20040096390A1 (en) * 2001-10-17 2004-05-20 Norihisa Kobayashi Flue gas desulfurization apparatus and flue gas desulfurization system, and method for operating flue gas desulfurization apparatus
CN103007718A (zh) * 2012-09-12 2013-04-03 河南绿典环保节能科技有限公司 一种烟气湿式氧化还原脱硫及资源化利用方法
CN107789953A (zh) * 2016-08-31 2018-03-13 中国石油化工股份有限公司 烟气脱硫的方法及装置

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
PL107500B1 (pl) * 1977-03-30 1980-02-29 Inst Chemii Fizycznej Pan Sposob wytwarzania kwasu siarkowego,zwlaszcza do produkcji nawozow fosforowych
DE3742838A1 (de) * 1987-12-17 1989-07-13 Kronos Titan Gmbh Verfahren zur herstellung von titandioxid-pigmenten

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2188342A (en) * 1936-07-29 1940-01-30 Ohio Rubber Co Manufacture of vehicle floor mats
DE1567451A1 (de) * 1951-01-28 1970-08-06 Duisburger Kupferhuette Verfahren zur Gewinnung von Schwefelsaeure aus SO2-haltigen Abgasen,vorzugsweise Roestereiabgasen
US2926999A (en) * 1958-02-24 1960-03-01 Tennessee Valley Authority Recovery of sulfur dioxide from waste gases

Cited By (43)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3947546A (en) * 1972-05-31 1976-03-30 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process for the purification of gaseous effluents
US3932585A (en) * 1972-09-12 1976-01-13 Nippon Kokan Kabushiki Kaisha Method of removing nitrogen oxides from plant exhaust
US3947560A (en) * 1973-03-15 1976-03-30 Nippon Oil Company, Ltd. Process for oxidizing sulfur dioxide
US4100259A (en) * 1973-07-26 1978-07-11 Compagnie Industrielle Des Telecommunications Cit-Alcatel Process and apparatus for the purification of fumes and gases and for the production of sulfuric acid
US4101635A (en) * 1973-09-03 1978-07-18 Nippon Oil Company Ltd. Method for regenerating and recycling catalyst for oxidation of sulfur dioxide
US3962864A (en) * 1973-09-20 1976-06-15 Rolls-Royce (1971) Limited Gas turbine power plant with exhaust treatments for SO2 removal
US3983217A (en) * 1973-09-26 1976-09-28 Kurashiki Boseki Kabushiki Kaisha Method for removing sulfur dioxide from waste gases
US4011298A (en) * 1973-12-18 1977-03-08 Chiyoda Chemical Engineering & Construction Co. Ltd. Method for simultaneous removal of SOx and NOx
US3920421A (en) * 1974-01-15 1975-11-18 Chemsoil Corp Removal of oxides of nitrogen from gas streams which also contain sulfur dioxide
US4035470A (en) * 1974-11-02 1977-07-12 Fuji Kasui Engineering Co., Ltd. Process for removing sulfur oxides and/or nitrogen oxides from waste gas
US3988129A (en) * 1974-12-16 1976-10-26 Union Carbide Corporation Process for removing sulfur dioxide from gas streams
US4070441A (en) * 1975-01-31 1978-01-24 American Electronic Laboratories, Inc. Method of removing sulfur dioxide from flue gases
US4157988A (en) * 1975-01-31 1979-06-12 American Electronic Laboratories, Inc. Method and composition for removing sulfur dioxide from flue gases
US4061743A (en) * 1975-05-06 1977-12-06 Fuji Kasui Engineering Co., Ltd. Exhaust gas scrubbing process
US4092401A (en) * 1976-01-09 1978-05-30 Compagnie Royale Asturienne Des Mines Process for reutilization of iron chlorides in aqueous solution
US4156712A (en) * 1976-02-28 1979-05-29 Chiyada Chemical Engineering & Construction Co., Ltd. Gas-liquid contacting method
US4239515A (en) * 1976-08-10 1980-12-16 Chiyoda Chemical Engineering & Construction Co., Ltd. Gas-liquid contact reaction apparatus
US4239737A (en) * 1977-01-14 1980-12-16 Italsider S.P.A. Method for removing sulfur dioxide
US4284608A (en) * 1977-07-18 1981-08-18 American Electronic Laboratories, Inc. Process for regenerating sulfur dioxide gas scrubbing solutions
US4123355A (en) * 1977-11-21 1978-10-31 Nasa Simultaneous treatment of SO2 containing stack gases and waste water
US4420465A (en) * 1981-06-22 1983-12-13 Mitsubishi Jukogyo Kabushiki Kaisha Process for desulfurizing an exhaust gas
US4502901A (en) * 1983-10-19 1985-03-05 National Gypsum Company Manufacture of gypsum board from FGD gypsum
US4552744A (en) * 1984-02-10 1985-11-12 Atomic Energy Of Canada Limited Process for the production of sulfuric acid using coated catalysts
US4657746A (en) * 1985-02-18 1987-04-14 Inco Limited Scrubbing of sulfur dioxide with lime slags
US4830718A (en) * 1985-10-21 1989-05-16 John Stauffer Removal of sulfur dioxide (SO2) from waste gases and recovery as sulfuric acid
US4986966A (en) * 1986-06-09 1991-01-22 Northern States Power Company Retrofit flue gas scrubber system
WO1987007527A1 (en) * 1986-06-09 1987-12-17 Northern States Power Company Flue gas scrubber system
US4762686A (en) * 1986-06-09 1988-08-09 Northern States Power Company Flue gas scrubber system
US4853195A (en) * 1986-06-09 1989-08-01 Northern States Power Company Flue gas scrubber system
US4861558A (en) * 1986-06-09 1989-08-29 Northern States Power Company Flue gas scrubber system with chloride removal
WO1988009695A1 (en) * 1987-06-12 1988-12-15 Northern States Power Company Flue gas scrubber system
WO1990012753A1 (en) * 1988-12-30 1990-11-01 Stauffer John E Removal of sulfur dioxide (so2) from waste gases and recovery as sulfuric acid
AU622372B2 (en) * 1988-12-30 1992-04-02 John E. Stauffer Removal of sulfur dioxide from waste gases and recovery as sulfuric acid
US6531104B1 (en) 2000-11-21 2003-03-11 Alstom (Schweiz) Ag Process for the absorption of sulfur oxides and the production of ammonium sulfate
US20040096390A1 (en) * 2001-10-17 2004-05-20 Norihisa Kobayashi Flue gas desulfurization apparatus and flue gas desulfurization system, and method for operating flue gas desulfurization apparatus
US20050025689A1 (en) * 2001-10-17 2005-02-03 Norihisa Kobayashi Flue gas desulfurization apparatus, flue gas desulfurization system, and method for operating flue gas desulfurization apparatus
US20050025679A1 (en) * 2001-10-17 2005-02-03 Norihisa Kobayashi Flue gas desulfurization apparatus, flue gas desulfurization system, and method for operating flue gas desulfurization apparatus
US6946108B2 (en) * 2001-10-17 2005-09-20 Mitsubishi Heavy Industries, Ltd. Flue gas desulfurization apparatus and flue gas desulfurization system, and method for operating flue gas desulfurization apparatus
US7335340B2 (en) 2001-10-17 2008-02-26 Mitsubishi Heavy Industries, Ltd. Flue gas desulfurization apparatus and flue gas desulfurization system
CN103007718A (zh) * 2012-09-12 2013-04-03 河南绿典环保节能科技有限公司 一种烟气湿式氧化还原脱硫及资源化利用方法
CN103007718B (zh) * 2012-09-12 2015-03-18 河南绿典环保节能科技有限公司 一种烟气湿式氧化还原脱硫及资源化利用方法
CN107789953A (zh) * 2016-08-31 2018-03-13 中国石油化工股份有限公司 烟气脱硫的方法及装置
CN107789953B (zh) * 2016-08-31 2021-03-02 中国石油化工股份有限公司 烟气脱硫的方法及装置

Also Published As

Publication number Publication date
AU4030572A (en) 1973-09-27
FR2132186B1 (no) 1975-06-13
DE2215177C3 (de) 1981-06-11
GB1389730A (en) 1975-04-09
AU455259B2 (en) 1974-11-21
NL7203550A (no) 1972-10-03
DE2215177A1 (de) 1972-10-12
IT969503B (it) 1974-04-10
CA970932A (en) 1975-07-15
FR2132186A1 (no) 1972-11-17
SE384015B (sv) 1976-04-12
NL168321C (no)
NL168321B (nl) 1981-10-16
DE2215177B2 (de) 1980-09-11

Similar Documents

Publication Publication Date Title
US3836630A (en) Method for treatment of gas containing sulfur dioxide
US3838191A (en) Continuous process for scrubbing so2 from a gas stream containing so2 and o2
US3911093A (en) Recovery of SO{HD 2 {B from waste gas emissions
US4049399A (en) Treatment of flue gases
US4102982A (en) Process for treating stack gases
US4198380A (en) Absorption of sulfur oxides from hot gases
US4011298A (en) Method for simultaneous removal of SOx and NOx
US3985860A (en) Method for oxidation of SO2 scrubber sludge
US3775532A (en) Removal of sulfur dioxide from gas streams
US4246245A (en) SO2 Removal
SE431865B (sv) Forfarande for avlegsnande av kveveoxider
US3676059A (en) Sulfate control in ammonia flue gas desulfurization
US4133650A (en) Removing sulfur dioxide from exhaust air
US4579727A (en) Oxidative removal of hydrogen sulfide from gas streams
US5035810A (en) Process for treating wastewater which contains sour gases
US3821110A (en) Sour water purification process
US4108969A (en) Process for the removal of SO2 from a stack gas, absorptive medium for use in process and process for preparing the absorptive medium
US4366134A (en) Flue gas desulfurization process
US3983225A (en) Recovery of sulfur from sulfur dioxide rich aqueous absorbents
US3849541A (en) Process for purifying fumes
US3533732A (en) Hydrogen sulfide removal from gas mixtures containing hydrogen sulfide and methane
US3953577A (en) Process for purifying gases containing HCN
US4012487A (en) Process for the removal of SO2 from a stack gas
US4113840A (en) Process for the removal of sulfur dioxide from exhaust flue gases
US3728433A (en) Continuous process for scrubbing sulfur dioxide from a gas stream